The characters of Thor and Loki only work in the MCU because they fundamentally belong to a different genre than everyone else. The plot of the Avengers happens because Loki, part of Thors world, bleeds into the "real" world and completely overwhelms everyone. In the Avengers scene where Thor and Loki are alone together and they start conversing in Shakespearean, for six minutes the movies genre changes and we're stuck in the opera. That's the ONLY way those two should be written as far as I'm concerned and any attempts to characterize them by fitting them into the rest of the MCU "genre" fundamentally misunderstands not only their characters but the functions they serve.
Call the Branagh movies "boring" all you want, but there's a reason the first two Thor movies were directed by a man whose main strengths were pretentious, melodramatic Shakespeare film adaptations
